What will happen to the aging U.S. fleet of nuclear reactors after Fukushima?Photo by Martin LaMonica/CNET

One year after the worst nuclear disaster in decades reinvigorated fears of nuclear energy in the United States, we're still waiting for the implementation of safety standards intended to address the problem.

In response to the devastating earthquake and tsunami that crippled the Fukushima Daiichi power plant in Japan one year ago, a task force created safety recommendations for existing plants to protect against natural disasters, such as earthquakes and floods, and extended loss of power. Final orders are expected soon, but the Nuclear Regulatory Commission (NRC) said this week it doesn't expect to be able implement the reforms within the five year deadline it set.

Even with the hardened security measures, seeing a technologically advanced country like Japan unable to effectively cope with the crisis was a sobering lesson on the limits of the safety system, even to people in the nuclear industry. A combination of insufficient planning and mistakes during the crisis led to events, including core meltdowns and the release of radiation, the nuclear industry never anticipated, said Ann MacLachlan, the European bureau chief for Platts Nuclear.

"True, the Fukushima plants were some of the oldest and [utility] Tepco had resisted improving the site protection because it didn't believe such an accident was possible," she said. "But the Fukushima scenario revealed potential vulnerabilities in all nuclear plants worldwide."

As a result, there's been a loss of trust in the nuclear industry and regulators' ability to prevent Fukushima-like disasters. In the U.S., this eroded confidence comes at a time when a number of plant operators are seeking to extend the lives of the aging fleet beyond their intended lives.

11

Aftermath of Japan's earthquake (photos)

The root cause for the meltdowns at Fukushima was operators' inability to cool reactors and spent fuel pools. Grid power was knocked out and then flooding disabled the back-up diesel generators needed to circulate cooling water. The heat from decaying radioactive material caused steam to build up and hydrogen explosions, which damaged the containment buildings and brought fears of even wider radiation leaks.

Because a number of U.S. power plants have the same or similar design as Fukushima, the NRC's latest safety recommendations address continuous power in a blackout, venting nuclear reactors, and monitoring spent fuel pools.

When these safety measures will be put in place, however, is tied to how the NRC enforces its upcoming orders. According to a Wall Street Journal report, NRC Chairman Gregory Jaczko agrees with the task force recommendation that new safety steps should be implemented regardless of cost, but that view is disputed by other commissioners.

Meanwhile, industry group the Nuclear Energy Institute (NEI) this week said plant operators have begun buying equipment, such as portable generators and diesel-driven pumps. These measures were done in to handle "extreme events" for which the 104 power plants in the U.S. weren't designed.

Watchdog the Union of Concerned Scientists said this week that this industry move was done to discourage the NRC from imposing more stringent requirements. Following the September 11 attacks, there were years of negotiating on how new rules would be put in place, a situation that should not be repeated for Fukushima-response measures, said Edwin Lyman, a senior scientist from the Union of Concerned Scientists' Global Security program.

"Just saying you shall do this without guidance leads to large uncertainty as has been documented after 9/11," Lyman said. "We think it's better to have orders and guidance out first and be as clear and specific as possible, so there's no confusion as to what's required for the industry."

Shut downs in U.S.?
Even as industry and regulators grapple with safety reforms, the worst disaster since Chernobyl in 1986 has energized opposition to existing nuclear power plants particularly in specific locations, such as seismically active zones or ones close to cities.

That resulted in drop in support for nuclear power in the U.S. after many years of growing support, according to Gallup. A NEI-sponsored survey from last month found public opinion for nuclear power continues to be favorable but slightly below the pre-Fukushima peak.

On a local level, however, a number of existing plants face opposition as they come up for license renewal. Eleven U.S. power companies are seeking 20-year license extensions for 15 nuclear power plants, pushing them to 60 years of operation, according to Bloomberg.

Citing evacuation difficulties in the case of an accident, New York governor Mario Cuomo is seeking to close the Indian Point power plant, which has had a string of accidents and supplies about 25 percent of the electricity to New York City and Westchester Country.

Opposition is also occurring in California, where there are fears that two nuclear power plants, San Onofre and Diablo Canyon, cannot withstand an earthquake and tsunami. Debate over license renewals is happening in Ohio, Florida, and Vermont, said Bloomberg.

16

Inside a nuclear power plant (photos)

Meanwhile, an unresolved problem the entire nuclear industry faces is the question of long-term storage of spent fuel. Right now, spent fuel rods are cooled off in pools and then encased in concrete casks and stored on site, rather than central repositories.

Finding replacements for today's nuclear plants is not a simple matter and more expensive than investing in upgrades. Compared with other power sources, nuclear plants take up far less space per megawatt-hour and don't have carbon emissions or conventional air pollutants during operation. In terms of cost, new nuclear plants, which have safer designs, are more expensive than building new natural gas plants.

In the end, Fukushima raised the question of what risk is acceptable for an energy source which supplies 20 percent of the country's baseload electric power. In the disaster's aftermath, there's a sharper eye on individual plants' vulnerabilities and regulators' ability to raise safety levels.

Tomorrow, we'll take a look at the global nuclear picture and how new technologies are changing the industry.